Joint Radar and Communication Application for Trac Safety System

University essay from KTH/Kommunikationsteori

Author: Raul Quijada; [2011]

Keywords: ;

Abstract:

The concept of “smart” cars or intelligent vehicles is presented as one of the most promising solutions to reduce the high mortality rate that occurs on the world’s roads nowadays. Besides, the recent publication of standards as the European Standard for Intelligent Transportation System  (ITS) or the international standard IEEE 802.11p confirm the importance of the future vehicle ‐to‐vehicle or vehicleto

‐infrastructure networks, which can diminish gridlocks or aid the driver with information about the road status or the weather forecast in order to prevent accidents, for instance. The main drawbacks of such intelligent network regarding the accident prevention lie in the presence of obstructing objects on the road or cars that do not implement this V2V system. Therefore, a radar application based on the used waveform for the V2V communication can be suitable as a direct method to avoid collisions. The aim of this thesis consists in the verification of the viability of a radar application in a V2V scenario. Thus, a thorough evaluation of the implemented V2V propagation channel has been performed so as to determine the main constraint factors, such as the power fading, Non Wide Sense Stationary Uncorrelated Scattering (NWSSUS) or the Doppler frequency, that can affect at detection and location application. From the conclusions obtained based on the characterization of a V2V channel, a radar algorithm has been designed as well as a tracking system. The design of the proposed radar algorithm is based on power peak detection that the estimated channel impulse response presents based on the reflected power originated by possible targets. The trilateration method is used for the location of these targets in the azimuth plane; thus, a Multiple Input Multiple Output system is required. In order to carry out this viability study, a MIMO structure 4x4 using OFDM with PSK or QAM as the modulation and over a real V2V propagation channel has been simulated. The Geometric Stochastic Channel Model (GSCM) is considered, since it contains most of the relevant channel ‐specific features; in particular it models the Non Wide Sense Stationary Uncorrelated Scattering (NWSSUS) behavior typical for such channels. Furthermore, the IEEE 802.11p standard has been implemented so as to simulate a scenario as close to reality as possible. The results obtained conclude with a positive result for the implemented scenarios. It is important to highlight that the extrapolation of this algorithm to other environments can lead to improvements or deteriorations of the probability of detection. However, the most valuable part of the thesis is the conclusion obtained for a radar implementation in a V2V scenario.

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